Isatoic anhydride derivatives and use as chain-extenders

ABSTRACT

Covers certain aromatic-amine amides which comprise the reaction product of a bis-amino-n propyl ether and an isatoic anhydride of the formula: ##STR1## where R is selected from the group consisting of hydrogen, alkyl, nitro, halo, hydroxy, amino, and cyano, and n is a number of 1-4. Also covers the use of said compounds as chain-extenders in polyurethane compositions. Such chain-extenders provide for the production of polyurethane elastomers having improved tensile strength, tear strength and elongation properties.

BACKGROUND OF THE INVENTION

When an organic polyisocyanate is reacted with a polyether polyol toproduce a polyurethane composition, various components are introducedinto the system in order to adjust the physical properties of theresulting polyurethane composition. For example, if a cellular productis desired, water or an appropriate blowing agent is added to thepolyurethane reaction mixture. In order to adjust properties of variouspolyurethane compositions such as the tensile strength, elongation, tearstrength, flexibility, the softness or hardness of the resultingcomposition, or the color, various other additives are used. Often theaddition of an additive to improve one particular property results inthe degradation of other properties of the polyurethane composition. Forinstance, an additive which increases the tensile strength of a solidpolyurethane composition, such as various fillers, may result in adecrease in the elongation of the resulting polyurethane composition.Therefore, it is necessary to achieve a balance of properties for agiven use.

Solid polyurethane compositions have found usefulness in gaskets,sealants, floor coverings, and the like. More recently, with the adventof molded, rigid plastics, it has become desirable to provide a flexiblepolyurethane mold for use in the place of the more expensivesilicone-type molds currently being used. In order for a polyurethanecomposition to be acceptable for this use, it must be soft and flexible,yet have good tensile and tear strength so that the mold does not becomeunusable after a short period of time due to tears or splits in the moldmaterial. Heretofore, polyurethane compositions have not been acceptablefor this purpose.

Polyurethane compositions generally in use as floor coverings aresystems dissolved in a solvent which are moisture-cured by theatmosphere after application on the floor. These floor coatings havebeen found to suffer considerably from "bleed through", especially whenplaced on a substrate which had previously been covered with some othertype of floor covering. While there are some single component floorcoatings (i.e., solvent types), these have been found to be lacking inone or more of the desired properties for an acceptable floor coating.To be an acceptable floor covering composition, it is desirable that theelastomer be strong, scuff-resistant and yet flexible enough to conformto shifts in the floor.

With the widespread use of foam crash pads in automobiles and the like,it has become desirable to develop a crash pad with a toughscuff-resistant skin which is integral to the foam of the crash paditself. Previously, it was necessary to line the mold in which the crashpad was to be cast with a decorative coating such as vinyl and the likein order to achieve the strength and scuff-resistance necessary for thepad, and yet maintain an attractive appearance of the crash pad itself.Previous attempts at producing a polyurethane foam crash pad having anintegral skin which would meet these qualifications have met withconsiderable difficulty and disappointing results.

The advantages and objects of our invention will be apparent to thoseskilled in the art, in view of the aforementioned background, thefollowing discussion and accompanying examples.

SUMMARY OF THE INVENTION

This invention relates to aromatic amine-amide compositions whichcomprise a reaction product of a bis-amino-n propyl ether and an isatoicanhydride of the formula: ##STR2## where R is selected from the groupconsisting of hydrogen, alkyl, nitro, halo, hydroxy, amino, and cyano,and n is a number of 1-4.

The invention also relates to the production of polyurethanecompositions having improved physical properties due to presence of theabove compounds which act as chain-extenders.

The chain-extender of the invention is incorporated into the reactionmixture of an organic isocyanate and an organic polymeric polyhydroxycompound such as polyester or polyether polyols used for the productionof polyurethane compositions, along with a urethane catalyst and variousadditives frequently used in the polyurethane art.

DETAILED DESCRIPTION OF THE INVENTION

Particularly preferred chain-extenders derived from certainbis-amino-n-propyl ethers have the following structural formula:##STR3## where R₁ is hydrogen or: ##STR4## and x is a number rangingfrom 2 to 6 or ##STR5##

In order to prepare the above compounds an isatoic anhydride of theformula: ##STR6## where R is selected from the group consisting ofhydrogen, alkyl, nitro, halo, hydroxy, amino, and cyano, and n is anumber of 1-4, is reacted with a bis-amino-n-propyl ether. The isatoicanhydrides are well known materials, and their preparation need not bediscussed in detail. A preferred reactant is isatoic anhydride itself,where R_(n) is H.

The bis-amino-n-propyl ether reactant is either ##STR7##

The above bis-amino ethers may be prepared via a number of knownmethods. Preferably they are made by first providing known diols orglycol ethers having the following formulae: ##STR8##

These diols and glycol ethers are then reacted with acrylonitrile byknown procedures to produce the dipropyl-dinitrile derivative which inturn are hydrogenated by known methods to produce the diamines. Use of anickel catalyst is typical in the hydrogenation step.

In order to make the products of the invention, the bis-amino ethers andisatoic anhydride are simply mixed together without necessity of solventor diluent and heated. When the reaction is finished, the productrequires no further treatment or purification. In addition, no catalystis necessary to effect the reaction. The products are generally viscousliquids (pourable when warm) rather than crystalline solids. Thetemperature of reaction may range from about 20° C. to about 200° C. ata pressure ranging from atmospheric pressure to about 1000 psig.

When one mole of the isatoic anhydride is added per mole of diamine onlyone of the terminal amine groups is reacted to produce a monoamide alsocontaining one aromatic and one aliphatic amine group. On the other handif two moles of the anhydride are reacted with one mole of the diamineboth terminal groups are reacted to produce a diamide structurecontaining two aromatic amine groups.

The above chain-extenders are particularly useful in preparing improvedsolid polyurethane compositions useful as sealants, floor coatings andmolds. In addition, when employing the additives of the invention onemay provide an integral skin on a foamed cellular polyurethanecomposition containing the chain-extenders of the invention. Thisintegral skinned cellular polyurethane composition produces a producthaving the desired properties of a foam crash pad in addition to havinga tough, scuff-resistant integral skin, thus, obviating the necessity oflining the mold with a separate skinning material.

As noted above in the production of polyurethane compositions, polymericpolyhydroxy compounds such as polyester or polyether polyols are reactedwith organic polyisocyanates to produce a polyurethane composition.Polyether polyols are described herein, and polyester polyols aredescribed in U.S. Pat. No. 3,391,093 for example. This reaction usuallyoccurs in the presence of a catalyst but may occur noncatalytically whena polyol containing a tertiary nitrogen atom is used. In the practice ofthe invention, the above-described chain-extenders are included in thisreaction mixture to produce improved polyurethane compositions. When asolid polyurethane composition is produced using the chain-extender ofthe invention, we have discovered that improved tensile strength, tearstrength and elongation results. With the chain-extender of ourinvention, strong yet flexible floor coverings and sealants arepossible. In additon, soft, flexible molds can be produced which haveimproved tear strength but yet have sufficient compression strength towithstand pressures produced when the mold made from our polyurethanecomposition must contain an expanding cellular plastic.

Suitable organic polyisocyanates useful in the practice of our inventionare those organic diisocyanates, triisocyanates and polyisocyanateswell-known in the polyurethane art. Mixed isomers of toluenediisocyanate which are readily commercially available such as thosedescribed in U.S. Pat. No. 3,298,976 and the like may be used.Especially preferred are diisocyanates and polyisocyanates prepared bythe phosgenation of the reaction product between aniline andformaldehyde such as 4,4'-diphenyl-methane diisocyanate,2,4'-diphenylmethane diisocyanate and higher functionalitypolyphenylmethylene polyisocyanates, hereinafter calledpolyarylpolyisocyanates. Especially preferred organic polyisocyanatesfor forming solid polyurethane compositions are diphenylmethanediisocyanate and modified diphenylmethane diisocyanates sold under thetrademark of ISONATE® 143L. Polyarylpolyisocyanates which are used inthe practice of our invention, particularly to produce cellularpolyurethanes, have a functionality of from about 2.0 to about 3.3. Anespecially preferred functionality range is from about 2.2 to about 2.9.

Polyether polyols useful in the practice of our invention are thosediols, triols, tetrols and mixtures thereof having a molecular weightfrom about 500 to about 10,000. The diols are generally polyalkyleneether glycols such as polypropylene ether glycol, polybutylene etherglycol, and the like, and mixtures thereof. Mixed polyether polyols canalso be used such as the condensation products of an alkylene oxide witha polyhydric alcohol having three or four primary hydroxyl groups suchas glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, andthe like. These polyether polyols are well-known and may be prepared byany known process such as, for example, the processes discussed inEncyclopedia of Chemical Technology, volume 7, pages 257-262, publishedby Interscience Publishers, Inc. in 1951.

As mentioned above, any suitable polyhydric polyalkylene ether may beused, such as, for example, the condensation product of an alkyleneoxide with a polyhydric alcohol. Any suitable polyhydric alcohol may beused such as, for example, ethylene glycol, 1,2-propylene glycol,1,3-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol,glycerine, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, andthe like. Any suitable alkylene oxide may be used such as, for example,ethylene oxide, propylene oxide, butylene oxide, amylene oxide, theirvarious isomers, and the like. Of course, the polyhydric polyalkyleneether polyols can be prepared from other starting materials such as, forexample, tetrahydrofuran, epihalohydrin, aralkylene oxides such as, forexample, styrene oxide, and the like. Polyhydric polyether polyolshaving three or four hydroxyl groups per molecule and a molecular weightof from about 2,000 to about 10,000 can be used. The polyol used can bea blend of diols with triols or tetrols to produce a polyol blend havingan average molecular weight of from about 500 to about 10,000. Blendeddiols and triols for use in solid polyurethane elastomers are generallydiscussed in U.S. Pat. No. 3,391,101. Most preferred for use eitheralone or blended with a diol are the polyoxyalkylene triols and tetrolshaving a molecular weight of from about 2,000 to about 7,000.

The polyether polyols may have primary or secondary hydroxyl grouptermination. When the polyhydric alcohol is reacted with an alkyleneoxide such as propylene oxide, butylene oxide, and the like, theterminal groups are predominantly secondary hydroxyl groups. However, itis within the scope of our invention to use polyether triols orpolyether tetrols which have from about 5 to about 15 wt. % ethyleneoxide added thereto in a final alkoxylation step by the knownalkoxylation processes in order to increase the terminal primaryhydroxyl content of the said polyether polyol. The manufacture ofethylene oxide "tipped" polyether polyols is generally discussed in U.S.Pat. No. 3,336,242.

As hereinbefore mentioned, the polyethyer polyol and the organicpolyisocyanate are reacted to form the polyurethane composition. Thisreaction may occur noncatalytically when a polyol is used which containstertiary nitrogen atoms or may be carried out in the presence of knownpolyurethane catalysts. The use of a separate catalyst is preferred. Thecatalyst employed may be any of the catalysts known to be useful forthis purpose, including tertiary amines and metallic salts. Suitabletertiary amines include N-methylmorpholine, N-ethylmorpholine,triethylenediamine, triethylamine, trimethylamine andN-dimethylethanolamine. Typical metallic salts include, for example, thesalts of antimony, tin, mercury and iron; for example, dibutyltindilaurate, phenylmercuric acetate and stannous octoate. The catalyst isusually employed in a proportion of from about 0.01% to 2% by weightbased on the weight of the overall composition.

Various additives can be employed to provide different properties, e.g.,fillers such as clay, calcium carbonate, talc, or titanium dioxide. Dyesand pigments may be added for color and anti-oxidants also may be used.

When the embodiment of our invention is practiced which involves theproduction of the self-skinning cellular polyurethane product, a foamingagent is employed which may be any of those known to be useful for thispurpose such as water, the halogenated hydrocarbons, and mixturesthereof. Typical halogenated hydrocarbons include but are not limited tomonofluorotrichloromethane, difluorodichloromethane, 1,1,2-trichloro-1,1,2-fluoroethane, methylene chloride, and the like. The amount offoaming agent employed may be varied within a wide range. Generally,however, the halogenated hydrocarbons are employed in an amount from 1to 50 parts by weight per 100 parts by weight of the polyol used in theproduction of the polyurethane composition. When water is employed asthe blowing agent, it is present in the amount of from 0.1 to 10 partsby weight per 100 parts by weight of the polyether polyol. Halogenatedhydrocarbon blowing agents for use in the production of a foamedpolyurethane composition are discussed in U.S. Pat. No. 3,072,582.

When it is desired to practice our invention in producing a floorcoating or sealant, it is often desirable to include therein apolyhydric cross-linking agent. Such cross-linking agents include, butare not limited to polyhydric alcohols such as glycerol,trimethylolpropane, 1,2,6-hexanetriol or pentaerythritol, or amines suchas ethylenediamine, N,N,N',N'-tetrahydroxypropyl-ethylenediamine, andthe like. These are included in the polyurethane composition such thatthey make up from about 0.02 wt. % to about 10 wt. % based upon theentire polyurethane composition. The use of such cross-linking agents iswell-known and those skilled in the art will be able to readilydetermine the amount and type of cross-linking to use in order toachieve desired physical properties.

The chain-extending agent of our invention as described above is used inboth solid polyurethane compositions and the self-skinning flexible orsemi-flexible polyurethane foam composition. The amount of thechain-extending agent may be as low as 0.1 weight percent based on thepolyol component in a solid elastomer polyurethane composition to about50 weight percent of the entire formulation when used in theself-skinning foam polyurethane composition. It may be used either aloneas the chain-extending agent or in conjunction with knownchain-extending agents such as 1,4-butanediol, diethylene glycol,4,4'-methylene bis(2-chloroaniline), and the like. However, we havediscovered that whether used alone or in conjunction with knownchain-extending agents, the chain-extender of our invention improves thetensile strength of the resulting polyurethane composition withoutdetriment to other desired physical properties. When used in solidpolyurethane compositions, the amount of 0.1 weight percent to about 15weight percent, based upon the weight of the polyether polyol, and morepreferably from about 0.5 to about 7 weight percent is employed.

In the production of the cellular self-skinning polyurethanecompositions, the chain-extending agent used in the practice of ourinvention would be present in the amounts of from 10 weight percent toabout 50 weight percent of the polyurethane reaction mixture, withpreferred amounts being from about 15 weight percent to about 35 weightpercent.

The chain-extender may be incorporated in the polyurethane compositionsof our invention which are produced by either "one-shot" or prepolymermethods. In the "one-shot" system all the reactants and additives aremixed and reacted simultaneously. In the prepolymer system a portion ofa polyhydroxy compound is reacted with the organic polyisocyanate toform a reaction product which has unreacted isocyanate groups. Thisreaction product is then mixed and reacted with the rest of thepolymeric polyhydroxy compound to form the polyurethane composition.

In reacting the polymeric polyhydroxy compound with the organicpolyisocyanate, the ratio of isocyanate groups to hydroxyl groups isbetween about 0.8 to about 1.5. This ratio, called the isocyanate index,is preferably between 0.9 and about 1.3 for the solid polyurethanecomposition and 0.8 to about 1.3 for the cellular self-skinning product.An especially preferred range for both polyurethane compositions is fromabout 0.95 to about 1.2. An isocyanate index of about 1.0 has been foundto give very good products.

The following examples will more particularly illustrate our inventionand should be considered for purposes of illustration only and notlimitation thereof.

EXAMPLE I

To a 500 ml 3-necked round bottomed flask fitted with mechanicalstirrer, thermometer, condenser and bubbler and N₂ inlet tube was added65.8 g of compound III below (0.3 mole).

It was heated to 120° C. under N₂ purge and 0.3 mole isatoic anhydride(48.9 g) was added over a 15 minute period. The reaction mixture washeated to 150° C. and held there for 2 hours and 15 minutes. The mobilebrown product weighed 103.4 g. Theory for 0.3 mole CO₂ loss (13.2 gloss) was 101.5 g. The product amine-amide contained 5.29 meq/g totaltitratable amine content and 0.027 meq/g tertiary amine content.

The reaction went as follows: ##STR9##

EXAMPLE II

To a 500 ml round bottom flask was added 43.8 g compound III (0.2 mole,or 0.4 equivalent) and it was heated to 120° C. under N₂. Then 65.2 g ofIA (0.4 mole, 0.4 equivalent) was added over a 35 minute period(120°-138° C.). The reaction mixture was then heated to 150° C. and heldthere for 2 hours. The clear brown product weighed 91.6 g. Theory for0.2 mole product (less the 0.4 mole CO₂ evolved) is 65.2+43.8=109.0g-(0.4×44)=109.0-17.6=91.4 g. Theory=91.4 g. Actual observed=91.6 g. Theproduct amine-amide contained 4.08 meq/g total amine content and 0.028meq/g tertiary amine content.

The reaction proceeded as follows: ##STR10##

EXAMPLE III

To a 500 ml round bottom flask as in Example I, was added 61.7 g ofdiamine II below (0.3 mole, 0.6 equivalent) which was heated under a N₂purge to 120° C., at which point 48.9 g of IA (0.3 mole, 0.3 equivalent)was added (spoon-wise) over a 5 minute period (120°-125° C.). Afteraddition was completed the reaction mixture was heated to 150° C. andheld there for 2 1/2 hours. The clear, mobile brown product (hot)weighed 97.9 g. (Theory for 0.3 mole CO₂ loss is61.7+48.9=110.6-13.2=97.4 g).

The product amide IX containing both aromatic and aliphatic amine groupshad a total titratable amine content of 5.65 meq/g and a tertiary aminecontent of 0.029 meq/g.

The reaction proceeded as follows: ##STR11##

EXAMPLE IV

To a 500 ml round bottom flask, as in Example I, was added 41.2 g ofdiamine II (0.2 mole or 0.4 equivalent) and this was heated to 130° C.under N₂ purge. Then 65.2 g IA (0.4 mole, 0.4 equivalent) was added overa 30 minute period (130° C.-137° C.). After the addition of IA wascomplete, the reaction mixture was heated to 150°-52° C. and held therefor 2 1/2 hours. The clear brown product weighed 89.0 g. Theoreticalproduct is 65.2+1.42=106.4 less the 0.4 mole CO₂ evolved or 106.4-17.6or 88.8 g theoretical. This compares very favorably with the 89.0 gactually observed. The product amide V containing 2 aromatic aminegroups had a total titratable amine content of 4.25 meq/g and a teritaryamine content of 0.037 meq/g.

The reaction proceeded as follows: ##STR12##

Flexible foams and other types of foams and elastomers are prepared fromthe above products of the invention and tensile and tear strengthproperties and elongation properties are improved though use of thesechain-extenders.

The compositions of the invention are also useful as curing agents inepoxy resin formulations, and in addition are useful in a variety ofend-uses where amines and/or amides may be employed.

we claim:
 1. A polyurethane composition prepared by reacting an organicpolyisocyanate with a polyhydroxy compound and a chain-extending agentcomprising a compound of the formula: ##STR13## wherein R is selectedfrom the group consisting of hydrogen, alkyl, nitro, halo, hydroxy,amino and cyano, n is a number of 1-4, x is a number of from 2 to 6 andR₁ is hydrogen or ##STR14##
 2. The polyurethane of claim 1 wherein saidchain-extending agent has the following structural formula: ##STR15## 3.The polyurethane composition of claim 1 wherein said chain-extendingagent has the following structural formula: ##STR16##